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Gregory Mendell LIGO Hanford Observatory

Gravitational Waves From Neutron & Strange Quark Stars. Gregory Mendell LIGO Hanford Observatory. Supported by the National Science Foundation. http://www.ligo.caltech.edu. The Neutron Star Idea. SN 1987A.

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Gregory Mendell LIGO Hanford Observatory

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  1. Gravitational Waves From Neutron & Strange Quark Stars Gregory Mendell LIGO Hanford Observatory Supported by the National Science Foundation http://www.ligo.caltech.edu LIGO-G040443-00-W

  2. The Neutron Star Idea SN 1987A • Chandrasekhar 1931: white dwarf stars will collapse if M > 1.4 solar masses. Then what? • Chadwick 1932: discovers the neutron. • Landau 1932: suggests stars have neutron cores. • Oppenheimer & Volkoff 1939: work out NS models. • Baade & Zwicky 1934: suggest SN form NS. http://www.aao.gov.au/images/captions/aat050.html Anglo-Australian Observatory, photograph by David Malin. (http://www.jb.man.ac.uk/~pulsar/tutorial/tut/tut.html; Jodrell Bank Tutorial) LIGO-G040443-00-W

  3. Discovery of Pulsars • Bell notes “scruff” on chart in 1967. • Close up reveals the first pulsar (pulsating radio source) with P = 1.337 s. • Rises & sets with the stars: source is extraterrestrial. • LGM? • More pulsars discovered indicating pulsars are natural phenomena. • Hewish, wins 1974 Nobel Prize. www.jb.man.ac.uk/~pulsar/tutorial/tut/node3.html#SECTION00012000000000000000 A. G. Lyne and F. G. Smith. Pulsar Astronomy. Cambridge University Press, 1990. LIGO-G040443-00-W

  4. Pulsars = Neutron Stars • From the Sung-shih (Chinese Astronomical Treatise): "On the 1st year of the Chi-ho reign period, 5th month, chi-chou (day) [1054 AD], a guest star appeared…south-east of Tian-kuan [Aldebaran].(http://super.colorado.edu/~astr1020/sung.html) • Pacini 1967: neutron stars power the crab nebula • Gold 1968: pulsars are rotating neutron stars. • orbital motion • oscillation • rotation http://antwrp.gsfc.nasa.gov/apod/ap991122.html Crab Nebula: FORS Team, 8.2-meter VLT, ESO LIGO-G040443-00-W

  5. Pulsars Seen and Heard Play Me (Vela Pulsar) http://www.jb.man.ac.uk/~pulsar/Education/Sounds/sounds.html Jodrell Bank Observatory, Dept. of Physics & Astronomy, The University of Manchester (Crab Pulsar) http://www.noao.edu/image_gallery/html/im0565.html Crab Pulsar: N.A.Sharp/NOAO/AURA/NSF LIGO-G040443-00-W

  6. Why Neutron Stars? • Fastest pulsar spins 642 times per seconds; R < 74 km • Thermal observations and theory suggest R ~ 5-15 km Masses ~ 1.4 Solar Masses www.physik.uni-muenchen.de/sektion/suessmann/astro/cool/ S. E. Thorsett and D. Chanrabarty, astro-ph/9803260 LIGO-G040443-00-W

  7. The back of the envelope please… Don’t take this the wrong way… 1.4 Solar Masses 1.4(1.99 × 1033 g) ------------------------ = -------------------- 10 km Sphere 4/3(106 cm) 3 Average density = 6.7 × 1014 g/cm 3 Mass neutron 1.67 × 10-24 g ------------------------ = -------------------- Volume neutron 4/3  (10-13 cm) 3 = 4.0 × 1014 g/cm 3 (billion tons/teaspoon) … but parts of you are as dense as a neutron star. p + e  n +e (inverse beta and beta decay) p + e = n (beta equilibrium) np = ne (charge neutrality) Nuclear density: 95% n, 5% p & e Seen: SN 1987A! LIGO-G040443-00-W

  8. More on Pulsars Known: 1000+ Unknown: up to 100,000 in the Milkyway. http://online.itp.ucsb.edu/online/neustars00rmode/kaspi/oh/05.html; Vicky Kaspi McGill University, Montreal Canada Cosmic lighthouses with terra-gauss magnetic fields ! D. Page http://www.astroscu.unam.mx/neutrones/home.html Respun to 642 Hz! In theory up to 2 kHz. LIGO-G040443-00-W http://astrosun2.astro.cornell.edu/academics/courses/astro201/pulsar_graph.htm

  9. What else is seen? HMXBs LMXBs http://www.astroscu.unam.mx/neutrones/home.html Magnetars Pulsar Glitches http://www.jb.man.ac.uk/~pulsar/tutorial/tut/tut.html http://antwrp.gsfc.nasa.gov/apod/ap980527.html Robert Mallozzi (UAH, MSFC) LIGO-G040443-00-W

  10. Now it gets interesting… • Fermi Temp = 1012 K • NS born at 1011 K, cools below 109 K within a year; BCS superfluids form. • Cools to 106 K over 107 K yrs. • NS are compact “cold” degenerate objects; GR & QM required to understand. D. Page http://www.astroscu.unam.mx/neutrones/home.html LIGO-G040443-00-W

  11. …and strange… http://chandra.harvard.edu/resources/illustrations/neutronstars_4.html NASA/CXC/SAO LIGO-G040443-00-W

  12. … and hyper-stranger still! LIGO-G040443-00-W

  13. Strange Stars in the News LIGO-G040443-00-W

  14. Recent Papers LIGO-G040443-00-W

  15. Some Of The Big Questions? • What is the NS/SQS max. mass; min radius? (1.4-3.5 M? R = ?) • How fast can NS/SQS spin (up to 2 kHz?) and what controls their spin cycles? • What are the final states of matter before collapse to BH, i.e., what’s inside these stars, really? • Are quark nuggets hitting the Earth? (Ice-9 Scenerios?) J. M. Lattimer & M. Prakash, astro-ph/0405262 LIGO-G040443-00-W

  16. Laser Interferometer Gravitational-wave Observatories Gravitational-wave Strain: LIGO is a lab looking for direct detection of GW’s. LIGO is an observatory, “listening” for GW’s cosmic spacetime vibrations. Figures: K. S. Thorne gr-qc/9704042; D. Sigg LIGO-P980007-00-D LIGO-G040443-00-W

  17. Wobbling star Accreting star “Mountain” on star Oscillating star Continuous Periodic Gravitational-Wave Sources Free Precession Wobble Angle  Triaxial Ellipsoid: Ellipticity  Mode with Saturation Amplitude A LMXB: e.g., Sco X-1: balance GW torque with accretion torque. A. Vecchio on behalf of the LIGO Scientific Collaboration : GR17 – 22nd July, 2004 LIGO-G040443-00-W

  18. The back of the envelope please… Approximate forms of the Quadrupole Formula • Triaxial ellipsoid: h ~ (G/c4) MR24frot2/r ~ 10–26 (for ellipticity ~ 10–6, frot = 200 Hz, M = 1.4 M, R = 106 cm, r = 1 kpc = 3 1021 cm) • Precession: h ~ (G/c4) sin (2)  MR2frot2/r ~ 10-27 (for ellipticity ~ 10-6; wobble angle  = /4, etc…) • LMXB Sco-X1: h ~ 10-26 (balance GW torque with accretion torque) • R-modes: h ~ (G/c4) MA2R2 (16/9) frot2/r ~ 10–26 ( for saturation amplitude A ~ 10–3, etc…) • Pulsar Glitch h ~ (G/c4) MA2R2frot2/r ~ 10 –32 ( for glitch amplitude A ~ 10–6, etc…) LIGO-G040443-00-W

  19. LSC Period/CW Search GroupSearch Techniques • ~ 30+ members of the LIGO Science Collaboration. • Has developed Coherent & Incoherent Search Methods • Known, Targeted,and All Sky Searches are underway. LIGO-G040443-00-W

  20. Sensitivity Curves The r-mode saturation amplitude was thought to be much larger in 2000 Figure: P. Brady ITP seminar summer 2000 LIGO-G040443-00-W

  21. Coherent Power vs. Tobs LIGO-G040443-00-W

  22. Incoherent Power vs. Tobs LIGO-G040443-00-W

  23. Phase Modulation LIGO-G040443-00-W

  24. Frequency Modulation • The frequency is modulated by the intrinsic frequency evolution of the source and by the doppler shifts due to the Earth’s motion • The Doppler shifts are important for observation times Schutz & Papa gr-qc/9905018; Williams and Schutz gr-qc/9912029; Berukoff and Papa LAL Documentation LIGO-G040443-00-W

  25. Amplitude Modulation Figure: D. Sigg LIGO-P980007-00-D LIGO-G040443-00-W

  26. Maximum Likelihood Likelihood of getting data x for model h for Gaussian Noise: Chi-squared Minimize Chi-squared = Maximize the Likelihood LIGO-G040443-00-W

  27. Coherent Match Filtering Jaranowski, Krolak, & Schutz gr-qc/9804014; Schutz & Papa gr-qc/9905018; Williams and Schutz gr-qc/9912029; Berukoff and Papa LAL Documentation LIGO-G040443-00-W

  28. The StackSlide Search Bins with frequency domain data, e.g., from SFTs or F-statistic. • An incoherent search method that stacks and slides power to search for periodic sources. (P. Brady & T. Creighton Phys. Rev. D61 (2000) 082001; gr-qc/9812014.) • The periodic search is computationally bound. A hierarchical approach that combines coherent & incoherent methods is needed to optimize sensitivity. • Sources like LXMBs with short coherence times (~ 2 weeks) require incoherent methods. • Mendell and Landry are developing the StackSlide Search for the CW group. (The group also uses Hough Transforms and Power Flux, for incoherent searches.) • Stack the power. • Slide to correct for spindown/doppler shifts. • Sum and search for significant peaks. LIGO-G040443-00-W

  29. Validation: Fake Pulsar vs Fake Instrument Line LIGO-G040443-00-W

  30. Sky Distribution of PowerFake Pulsar and Fake Noise: LIGO-G040443-00-W

  31. Sky Distribution of PowerFake Instrument Line and Noise LIGO-G040443-00-W

  32. Sky Distribution of PowerFake Noise Only: LIGO-G040443-00-W

  33. StackSlide Pipeline Compute PSDs from SFTs Normalize PSDs Select template Veto Instrument Lines Slide Stacks and SUM Veto on Coincidence Find peaks above threshold Veto SNR does not grow as T Veto peak based on width Line Removal Veto SFTs SFTs are generated only once Parameter space metric placement Raw Data Input a band from SFTs Normalize SFTs Uniform placement Template placement Template placement Compute F-statistic for each point in the course grid Output event No Monte Carlo Yes Detection candidate Set UL from LE LIGO-G040443-00-W

  34. Statistics Gaussian Noise Rayleigh Dist. 2 variable, with 2 degrees freedom 2 Distribution LIGO-G040443-00-W

  35. Statistics: False Alarm Rate; False Dismissal Rate and UL from LE LIGO-G040443-00-W

  36. PSR J1939+2134 P = 0.00155781 s fGW = 1283.86 Hz dP/dt = -1.0511 10-19 s/s D = 3.6 kpc Result: S1 Coherent Search -- GEO -- L 2km -- H 4km -- L 4km S1 sensitivities <h0> • ho<1.4x10-22 constrains ellipticity < 2.7 x 10-4 (M=1.4 Msun, r=10 km, R=3.6 kpc) B Allen and G Woan on behalf of the LIGO Scientific Collaboration : Amaldi 9 July, 2003. LIGO-G040443-00-W

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